Electrical Stimulation of Induced Seizures (ESIS) in the Pediatric Epilepsy Monitoring Unit (EMU): A Pilot Study Demonstrating Safety, Tolerability and Yield
Abstract number :
1.175
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2022
Submission ID :
2204831
Source :
www.aesnet.org
Presentation date :
12/3/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:26 AM
Authors :
S. Katie Ihnen, MD, PhD – Cincinnati Children's Hospital Medical Center; Hansel Greiner, MD – Cincinnati Children's Hospital; Francesco Mangano, MD – Cincinnati Children's Hospital; Jesse Skoch, MD – Cincinnati Children's Hospital; Darcy Krueger, MD, PhD – Cincinnati Children's Hospital; Ravindra Arya, MD, DM – Cincinnati Children's Hospital
Rationale: Children and adolescents with drug-refractory epilepsy (DRE) are increasingly referred for epilepsy surgery, even with multifocal and MRI-negative etiologies. To identify the surgical target, or epileptogenic zone (EZ), many patients undergo presurgical invasive EEG monitoring to capture spontaneous seizures, a process that can be unpredictable, lengthy and even fail to reveal a dominant EZ. Electrical stimulation of induced seizures (ESIS) using stereo EEG (sEEG) has been shown to be safe and valid for EZ delineation in adults with DRE, providing data complementary to that from spontaneous seizures. However, ESIS is not routinely used in the pediatric Epilepsy Monitoring Unit (EMU), in part due to concerns about safety, tolerability and yield. The objective of this pilot study was to examine those concerns in a large, single-center pediatric EMU.
Methods: Consecutive patients with DRE undergoing sEEG were eligible. ESIS was performed using published parameters. Bipolar stimulation using a skip approach targeted all gray matter contacts. Low (1 Hz) and high (50 Hz) frequency pulse trains were performed with pulse durations of 250 to 500 µs and train durations of 30s for low and 5s for high frequency trials. Charge density was < 57 µC/cm2. Induced seizures were compared to spontaneous seizures for electroclinical concordance. Additional features including replicability were assessed. Patients’ and caregivers’ concerns about the study were surveyed pre- and post- participation.
Results: Eleven of 12 (92%) eligible patients enrolled; one patient participated during two sEEG admissions, for a total of 12 distinct ESIS datasets from 11 patients (4F, 7M). A variety of epilepsy etiologies (e.g., Tuberous Sclerosis Complex, perinatal brain injury) and ages (3-23y, median 12) was represented, as were bilateral (n=3) and unilateral (n=4 right, n=5 left) sEEG implants. ESIS data sets were obtained over 1-4 sessions, starting 24-48 hours after implant and comprising 17 to 253 trials (median 139), for a study duration of 30 to 220 minutes (median 129). Anti-seizure medications were continued (n=4), reduced (n=2) or held (n=6), per the treating clinician. At least one seizure with habitual features was induced in 7 of 12 datasets (58%), with a range of 1-8 (median 1) induced seizures. Both low (n=3 datasets) and high (n=5 datasets) frequency stimulation induced seizures. One patient (20y M) withdrew consent after a single induced seizure. One patient (17y F) had an induced seizure requiring rescue medication, per her home plan; she responded rapidly to IV diazepam. While pre-study survey responses indicated initial reservations about participating, post-study survey responses were overwhelmingly positive.
Conclusions: In a pediatric EMU, ESIS can be employed safely in the beginning of an sEEG admission, requiring on average about two hours. It is well-tolerated by patients and families. With habitual seizures induced in 58% of datasets, the yield is comparable to that seen in adults. Extensions of this work will examine the clinical validity of ESIS in children and adolescents with DRE.
Funding: Network for Excellence in Neuroscience Clinical Trials, 5U24NS107200-04 (Ihnen, fellowship awardee)
Neurophysiology